Inorganic Chemistry, Vol.48, No.4, 1398-1406, 2009
An Acyclic Dimer of Cyclodiphosphazane {(BuHN)-Bu-t((BuNP)-Bu-t)(2)OCH2}(2) Containing Alkoxo and Amido Functionalities: Synthesis, Derivatization, Bi- (Pd-II, Rh-I), and Tetranuclear (Pd-II, Au-I, (RhAuI)-Au-I) Transition Metal Complexes
Acyclic bis(cyclodiphosphazane) [(BuHN)-Bu-t((BuNP)-Bu-t)(2)OCH2](2) (2) containing alkoxo and amido functionalities was synthesized by reacting cis-[(BuHN)-Bu-t((BuNP)-Bu-t)(2)Cl] (1) with ethylene glycol and upon further treatment with 4 equiv of elemental sulfur or selenium affords the corresponding tetrachalcogenides [(BuHN)-Bu-t((BuNPE)-Bu-t)(2)OCH2](2) (3, E = S; 4, E = Se) in quantitative yield. The reaction of 2 with 2 equiv of elemental sulfur results in the oxidation of only the amido-phosphorus atoms to form the di(sulfide) derivative [(BuHN)-Bu-t(S)P(mu-(BuN)-Bu-t)POCH2](2) (5). The reaction of 2 with 2 equiv of [PdCl(eta(3)-C3H5)](2) afforded the tetrametallic complex [{Pd(eta(3)-allyl)Cl)(4)((BuHN)-Bu-t((BuNP)-Bu-t)(2)OCH2}(2)] (7) containing four independent [PdCl2(eta(3)-C3H5)] moieties each coordinated to a phosphorus atom. In contrast, the reaction between [Pd(PEt3)Cl-2](2) and 2 leads to the addition of two metal atoms with the formation of [{Pd(PEt3)Cl}(2)-{(BuHN)-Bu-t((BuNP)-Bu-t)(2)OCH2}(2)] (8), in which alternating phosphorus atoms of the bis(cyclodiphosphazane) are coordinated to palladium. Interestingly, the palladium(II) atom coordinated to the phosphorus atom bearing the t-butylamino substituent adopts a trans geometry, whereas that coordinated to the phosphorus atom connected to the -OCH2CH2O- linker prefers a cis conformation. The reaction between 2 and [Rh(COD)Cl]2 produces exclusively the bimetallic complex [{Rh(COD)Cl}(2){(BuHN)-Bu-t((BuNP)-Bu-t)(2)OCH2}(2)] (6) irrespective of the stoichiometry of the reactants and the reaction conditions. In complex 6, only the alkoxo-phosphorus atoms are coordinated. However, complex 6 upon treatment with AuCl(SMe2) in a 1:2 ratio gives the heterometallic tetrasubstituted complex [{Rh(COD)Cl}(2)(AuCl)(2){(BuHN)-Bu-t((BuNP)-Bu-t)(2)OCH2}(2)] (10). The reaction between 4 equiv of AuCl(SMe2) and 2 resulted in the formation of a tetrametallic gold complex [(AuCl)(4){(BuHN)-Bu-t((BuNP)-Bu-t)(2)OCH2}(2)] (9). The crystal structures of 2-4 and 7-10 are reported.